This invention pertains to an anti-projectile, anti-spall, anti-ricochet, trampoline-action armor panel. In particular, it pertains to such a panel which is formed preferably with a plural-layered armor core, or core structure, including a hardened-material tile strike layer, and a plurality of armoring back-up flexure, or flex, layers (or at least one such layer) arranged in a stack, with lateral edges in the stack bound against motion relative to one another. The panel of the invention further includes a load-managing, stranded, around-the-core enveloping core-wrap of a special nature, with a coating provided on the outside at least of the lateral edges and of the strike face of the panel, which coating is formed of a high-elastomer, self-puncture-healing and energy-dissipating material, which, as will be discussed, and among other things, enhances trampoline action in response to a projectile strike.
In further general terms, the panel is constructed preferably with a modular, tile-like configuration so that it can easily be organized with other modularly-related similar panels to form a protective shield on, adjacent, etc., a selected site or object. Appropriate attaching structure/mechanism may be suitably integrated into the panel during its construction, if desired, for enabling ready mounting and attaching of the panel in its intended operative location.
The mentioned back-up layers may be employed in different numbers depending upon the projectile threat level to which the panel's use is directed, and these back-up layers are preferably each formed with plural sub-layers of appropriately disposed aramid fibers, preferably in a fabric weave, which are suitably facially bonded internally to unify the layer. The hardened-material, preferably ceramic-tile, strike layer which defines the projectile strike side of the panel of this invention is preferably formed as a row-and-column array of smaller ceramic tile units. These tile units are disposed substantially in edge-adjacent-edge, slightly edge-spaced, lateral adjacency, with an appropriate, shock-absorbing, elastomeric binder resin disposed between these edges to maintain a desired slight amount of spacing between adjacent edges in order to minimize lateral telegraphing of impact shattering and fragmentation of one tile to its neighbors. This same resin is employed to bind the strike layer to one facial side of the stack of adjacent back-up layers, and the core-wrap structure to the opposite facial side of the back-up layer stack.
The edge binding, or anchoring, of the lateral edges of all of the back-up layers in the core of the panel of this invention via a suitable hot-melt adhesive effectively converts substantially the entire lateral edge perimeter (the perimetral boundary) of the back-up layer portion of the core into a non-relative-motion singularity. This singularity prevents these edges effectively from moving relative to one another during response to an impact, while at the same time permitting a kind of trampoline-like, broad-beam flexing across the broad expanses of all of the back-up layers collectively. The bound edge structure further accommodates interfacial sliding motion between the confronting faces (facial expanses) of these layers as a consequence of a projectile impact event. This edge-bound structure thus renders, or characterizes, a unique core arrangement which responds with what is referred to herein as trampoline-broad-beam, slide-face behavior. One way of thinking about, or visualizing, how this beam-like characterization/analogy attaches to the structure of the invention is to imagine viewing any number of transverse cross-sectional sections taken through the core stack of layers in any plane which effectively intersects the planes of these layers at right angles. Doing this, one will notice that what one sees in each of these view planes is an elongate, laminar, beam-like “section” with opposite ends effectively locked into unified and interconnected structures (the entire bound perimeter), and with central, laminar stretches between these ends bendable in response very much like what one would observe in the behavior of an elongate, double-end-supported beam structure in, for example, the frame of a building.
The stranded core-wrap structure employed herein is one wherein two, wrapped, fabric-like components are employed, each having what is referred to herein as a load-transmitting grain direction (a fiber-based direction) which is effectively defined by elongate, substantially parallel, elongate, tension-load-bearing (TLB) fibers, preferably aramid fibers. These elongate TLB fibers in each wrap component substantially parallel the grain direction of the component. The two wrap components are organized into overlapping adjacency with respect to one another in such a fashion that (a) their respective grain directions are disposed at angles, and preferably at right angles, relative to one another at the two locations where these two components extend across the broad faces of the panel of this invention, and (b), these same grain directions are aligned in a common direction along the lateral edges of the panel, and specifically in a common direction which extends substantially normally between what can be thought of as the planes of the strike and opposite faces of the finished panel.
Significantly, the portions of the core-wrap structure which lie adjacent the bound edges of the back-up layers are adhered thereto, and this arrangement aids, as will be explained, in the trampoline response action of the panel of the invention. Additionally, in the region where these two core-wrap components centrally cross and overlap one another, they are anchored to that side of the stack of back-up layers which faces away from the strike layer of ceramic tiles.
The mentioned high-elastomer coating, which may be applied to the entirety of the surface areas of all sides of the panel of this invention, but which in the specific embodiment described herein extends over only the strike side and the lateral edges of the disclosed panel, operates as a significant energy dissipater with respect to an impacting projectile, such as a bullet, a fragmentation shrapnel-like shard, etc. This elastomer coating also integrates mechanically with the core-wrap structure, as will be explained, and co-acts therewith, along with the edge-bound core-structure back-up layers, via the connections which exist between these layers and the core-wrap structure, to enhance the broad-beam trampoline-response behavior of the overall panel.
In testing and observing the responses of many panels constructed in accordance with the teachings of this invention, we have observed that this panel not only is very effective in its role of defeating an incoming projectile threat, but also, after an impact has occurred, is strongly effective in preventing post-impact threat developments arising from spall. In other words, it does not allow the regeneration, so-to-speak, of fragmentation projectiles due, for example, to the breaking up of an incoming impacting projectile, or the breaking up of an internal armoring tile. Put another way, the panel appears to swallow/contain both impacting threat projectiles and the resulting internal fragments which may develop (as by bullet break-up and tile shattering) as a consequence of a received impact. The panel also is effective in greatly minimizing ricochets. Further, and as will be mentioned again later, the cooperative relationship which exists between the outer elastomer coating and the core-wrap structure, appears to handle an internal, blast-like, pressure-wave event, which immediately follows a projectile impact, in a unique outward-bulge-and-return manner.
All in all, the structure of the panel of this invention operates with a unique, broad-beam, trampoline-like and related actions which deal with a projectile impact through internal tile fragmentation to “burn” energy and break up a projectile, through energy dissipation occurring in the response provided by the elastomer layer, through broad-beam, trampoline-like flexure and yielding deflection which occurs in the behavior of the stacked assembly of the back-up layers included in the panel core, and through the bulge-and-return behavior just mentioned above. As will be seen, and as has been noted earlier, trampoline response is enhanced by the presence in the panel of the elastomer outer coating which is anchored to the panel edge regions in the immediately underlying core-wrap fabric structure.
Further, because of the unique edge-to-edge, resin-filled, shock-absorbing spacing which characterizes the strike layer of the employed hardened-material (ceramic) tile array, fragmentation of a directly hit tile effectively does not telegraph to its neighbors. Thus the armor panel of this invention has demonstrated a remarkable ability to receive and disable multiple, closely-spaced projectile impacts.
These and various other features and advantages which are offered by the invention will now become more fully apparent as the description which shortly follows is read in conjunction with the accompanying drawings.
While those skilled in the art will recognize from the description of this invention which now follows that various specific materials may be employed in different regions of the structure of the present invention, there are certain preferred materials upon which we have settled, and we here identify those materials.